Monitor 10's sealed?

[Mothra]

Newbie question, forgive me...

Shouldn't my Monitor 10's be airtight? When I gently press in on one of the 6.5 drivers, the PR will extend out in unison. If I hold the 6.5 in, and not release, the PR extends out, and then slowly pulls back in to it's original starting point. Shouldn't the PR extend out and then hold? Is this a normal occurance? Do I need to re-seal around my drivers?

* Disclaimer..the Monitor 10 used for this experiment was in no way harmed or abused. She is presently residing at a speaker retreat located in my HT. :D

[mhardy6647]

That's just what they should do. They are indeed airtight; the pressure you apply to one cone is relieved by the other moving in opposition. When the pressure's removed, the cone(s) relax.

The effect you describe could only happened if you added pressure irreversibly (i.e., added air to) the enclosure.

[outlander]

Mothra
I just tried your experiment on my 10B’s and this is what I found. I made a little fixture so when I pushed in on the PR it was pushed to a fixed position. When I pushed in on the PR the 6.5” mids extended away from the cabinet (as they should). Within the first few seconds of applying pressure to the PR, the mids relaxed by about 1/3, after about 60 seconds I removed the pressure and the mids returned the remaining 2/3 of travel to their original position. If you get a chance to do this to yours I would be interested to hear how you made out.

I’ve often wondered how air tight these speakers need to be. But when you think about it, I’m sure it’s not necessary that they be completely air tight because if it takes seconds for the air to escape, that’s an eternity compared to the time constant of a cycle in the 30Hz plus frequency range.
O